US6809911B2 - Safety switching device for safely switching off an electrical load - Google Patents

Safety switching device for safely switching off an electrical load Download PDF

Info

Publication number
US6809911B2
US6809911B2 US10/355,703 US35570303A US6809911B2 US 6809911 B2 US6809911 B2 US 6809911B2 US 35570303 A US35570303 A US 35570303A US 6809911 B2 US6809911 B2 US 6809911B2
Authority
US
United States
Prior art keywords
switching device
signal
unit
safety switching
machine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US10/355,703
Other languages
English (en)
Other versions
US20030137788A1 (en
Inventor
Rolf Dickhoff
Winfried Gräf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pilz GmbH and Co KG
Original Assignee
Pilz GmbH and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pilz GmbH and Co KG filed Critical Pilz GmbH and Co KG
Assigned to PILZ GMBH & CO. reassignment PILZ GMBH & CO. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DICKHOFF, ROLF, GRAF, WINFRIED
Publication of US20030137788A1 publication Critical patent/US20030137788A1/en
Application granted granted Critical
Publication of US6809911B2 publication Critical patent/US6809911B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
    • H01H47/002—Monitoring or fail-safe circuits
    • H01H47/004—Monitoring or fail-safe circuits using plural redundant serial connected relay operated contacts in controlled circuit
    • H01H47/005—Safety control circuits therefor, e.g. chain of relays mutually monitoring each other

Definitions

  • the present invention relates to a safety switching device for safely switching off an electrical load such as an electrically driven machine.
  • the invention relates in particular to a safety switching device having a failsafe disconnection unit as well as a signaling unit, to both of which an external control signal is jointly supplied.
  • the disconnection unit switches off the electrical load in a failsafe manner as a function of a defined signal state of the control signal, and the signaling unit produces an external reporting signal as a function of the defined signal state.
  • Safety switching devices like this are particularly used in industrial areas in order to carry out disconnection processes in a failsafe manner.
  • “Failsafe” in this context means that the switching device complies at least with Safety Category 3 of European Standard EN 954-1.
  • devices like these are used to stop a machine system from which a hazard originates, or to bring it to a safe state in some other way, as a reaction to the operation of an EMERGENCY OFF button or the opening of a guard door. It is also generally necessary to disconnect a machine or machine system entirely or at least partially in a failsafe manner in order to carry out maintenance or repair work.
  • a known safety switching device In order to allow a machine to be run down in a controlled manner before it is actually switched off, a known safety switching device has a first delay element, by means of which the switching-off process, that is to say the interruption of the power supply, is delayed by the first time interval. Before this time interval has elapsed, the signaling unit produces a state change in the external reporting signal, thus causing the control unit for the machine to bring it to the rest state.
  • the signaling unit essentially comprises two mutually redundant relays which, in contrast to the relays in the disconnection unit, trip without any delay when no current flows in their control circuit. In contrast, the relays in the disconnection unit have an off delay. Like the known safety switching device in total, the signaling unit is thus designed to be failsafe and thus produces a failsafe reporting signal. As already mentioned above, however, a safety switching device like this is complex and costly.
  • the signaling unit being a non-failsafe unit which produces a non-failsafe reporting signal at one output of the switching device.
  • the safety switching device In contrast to completely dispensing with the signaling unit, the safety switching device according to the invention has the advantage that the machine which is to be switched off can generally be run down in a controlled manner before being switched off. This avoids difficulties during restarting.
  • the signaling unit deactivates the reporting signal without any delay when the defined signal state occurs.
  • control signal includes an operating voltage for the switching device, with the defined signal state corresponding to absence of the operating voltage.
  • the safety switching device has a logic OR gate, which links the operating voltage to an externally supplied disconnection signal of a tripping element, with the defined signal state corresponding to absence of the operating voltage or to operation of the tripping element.
  • This measure provides two-channel drive for the safety switching device in a simple manner, thus further increasing the failsafety.
  • the signaling unit has a second delay element, by means of which the production of the reporting signal is delayed by a second time interval when the switching device is switched on.
  • This measure has the advantage that the supply voltage for the machine is already available in a stable manner before the signaling unit produces the external reporting signal and the operating control system for the machine in consequence causes the machine to run up.
  • this advantageous time sequence can be achieved without any additional external circuitry and timers, thus simplifying the use and the installation of the safety switching device according to the invention.
  • the disconnection unit has at least two mutually redundant switching means, which are arranged in series with one another.
  • the switching means have at least one positively-guided auxiliary contact, which is connected in a monitoring circuit.
  • the disconnection unit and the signaling unit are arranged in a common switching device enclosure.
  • This measure has the advantage that the safety switching device according to the invention is available as a compact component, thus considerably simplifying its installation in a machine system that is to be monitored. In this case, it is particularly advantageous that the time sequences between the disconnection unit and the signaling unit are controlled within the device, thus avoiding faults in the installation and undesirable manipulations.
  • FIG. 1 shows a schematic illustration of a safety switching device of a generic type, on which the present invention is based;
  • FIG. 2 shows a schematic illustration of an exemplary embodiment of the safety switching device according to the invention
  • FIG. 3 shows a first exemplary embodiment of the design of the signaling unit for the safety switching device shown in FIG. 2;
  • FIG. 4 shows a second exemplary embodiment of a signaling unit
  • FIG. 5 shows an illustration of the time relationships in the safety switching device according to the invention.
  • FIG. 6 shows a schematic illustration of a second exemplary embodiment of the safety switching device according to the invention.
  • a safety switching device of a generic type is annotated in its entirety by reference number 10 .
  • the safety switching device 10 is installed in a compact device enclosure 12 , which has numerous externally accessible connecting terminals.
  • the connecting terminals are in the form of screw terminals and are indicated in FIG. 1 in the usual manner for such switching devices.
  • the connecting terminals A 1 and A 2 form an input via which the safety switching device 10 is supplied with a device-internal operating voltage U B .
  • the operating voltage U B is passed via external links 14 between the terminals S 33 and S 34 , and terminals Y 1 and Y 2 , first of all to a series circuit 16 , which is formed from the auxiliary contacts of four relays K 1 , K 2 , K 4 and K 5 and to the control circuit of an off-delay relay K 3 as well as.
  • the auxiliary contacts of the relays K 1 , K 2 , K 4 and K 5 are break contacts, which are closed in the rest state.
  • relays K 1 , K 2 , K 4 and K 5 pull in, their auxiliary contacts in the series circuit 16 open, and the make contacts 24 , 26 , 28 , 30 close. Furthermore, the two further auxiliary contacts 36 , 3 B are closed and then maintain the current flow via the control circuits for the relays K 1 , K 2 , K 4 and K 5 irrespective of the operating position of the relay K 3 .
  • the relay K 3 trips once the predetermined off delay time has elapsed.
  • the make contacts 24 , 26 , 28 , 30 in the two output circuits of the safety switching device 10 are closed, so that a machine (not shown here) which is connected to the safety switching device 10 is switched on. If the operating voltage U B is removed from the input terminals A 1 , A 2 , all the contacts fall back to their rest position, as illustrated in FIG. 1 . This results in the current path between the terminals 32 and 33 being interrupted virtually at the same time. The current path between the terminals 34 and 35 is in contrast interrupted with a delay time, which corresponds to the off delay time of the relays K 4 and K 5 .
  • a machine which is to be switched off is supplied via the current path between the terminals 34 and 35 , while the reporting signal is passed via the current path between the terminals 32 and 33 .
  • the production of the reporting signal in this case requires just as many relays as for switching off the machine.
  • FIG. 2 an exemplary embodiment of a safety switching device according to the invention is annotated in its entirety, with reference number 40 .
  • Identical reference symbols in this case denote the same elements as in FIG. 1 .
  • the safety switching device 40 once again has the make contacts 24 , 26 (which are arranged in series) of the two relays K 1 and K 2 in its output circuit between the terminals 34 and 35 .
  • the input circuits of the relays K 1 and K 2 are initially supplied via the make contacts 18 , 20 of the relay K 3 , in the same way as the safety switching device 10 shown in FIG. 1 .
  • the relay K 3 trips with a delay time, and the input circuits of the relays K 1 and K 2 are supplied via the auxiliary contacts 36 and 38 , which are closed at this time.
  • the design of the safety switching device 40 corresponds to that of the safety switching device 10 .
  • the reference numbers 44 , 46 denote two capacitances, which are respectively connected in parallel with the control circuit of the relays K 1 and K 2 .
  • the two capacitances 44 , 46 are charged up.
  • the two capacitances 44 , 46 are discharged via the control circuits of the relays K 1 and K 2 .
  • the relays K 1 and K 2 do not trip, with their make contacts 24 , 26 opening, until after the capacitances have been discharged.
  • the machine 42 is thus switched off with a delay time T 1 , which corresponds to the discharge time for the capacitances 44 , 46 .
  • the capacitances 44 , 46 are thus first delay elements in the context of the present invention.
  • each of the two relays K 1 , K 2 has a poitively-guided auxiliary contact 50 , 52 , which is coupled to the relay K 3 such that the safety switching device 40 cannot be taken into operation if one of the make contacts 24 , 26 has fused.
  • the auxiliary contacts 50 , 52 are thus included in a monitoring circuit.
  • the safety switching device 40 has a signaling unit 54 which is not failsafe and which produces a reporting signal 58 , which is not failsafe, at an output terminal 56 .
  • the reporting signal 58 can thus be supplied in a simple manner to a control unit 60 for the machine 42 .
  • the output terminal 56 is connected directly to the operating voltage U B in order to produce the reporting signal 58 .
  • Preferred exemplary embodiments for the signaling unit 54 are, however, described with reference to the following figures.
  • the signaling unit 54 comprises an amplifier circuit comprising two transistors T 1 and T 2 , as well as a number of resistors R 1 to R 6 .
  • the reporting signal 58 is in this case tapped across the resistor R 6 at the collector of the transistor T 2 which, with the illustrated circuitry, means that the reporting signal 58 approximately corresponds to the operating voltage U B , when in the active state, while it is in a non-live, high-impedance state, when deactivated.
  • the circuit of the signaling unit 54 has an additional capacitance 62 added to it, which results in the reporting signal 58 assuming its active signal state only once the capacitance 62 has been largely charged up.
  • the production of the reporting signal 58 is delayed by a second time interval, which is governed by the capacitance 62 .
  • FIG. 5 again shows the time sequences for the safety switching device 40 in the form of a graph.
  • the operating voltage U B of the safety switching device 40 is switched on.
  • the make contacts 24 , 26 of the relays K 1 and K 2 pull in, so that the supply voltage U V is applied to the machine 42 .
  • the reporting signal 58 in contrast does not assume its active state until the second time interval T 2 has elapsed, which corresponds approximately to the time for charging up the capacitance 62 .
  • the reporting signal 58 reverts virtually at the same time to its deactivated, high-impedance state.
  • the make contacts 24 , 26 of the relays K 1 , K 2 remain closed until the capacitances 44 , 46 have been discharged.
  • the machine 42 is not disconnected from its power supply U V until the time interval T 1 has elapsed.
  • the control unit 60 for the machine 42 thus has sufficient remaining time to run down the machine 42 in a controlled manner before switching off the supply voltage U V .
  • FIG. 6 a further exemplary embodiment of a safety switching device according to the invention is annotated in its entirety by reference number 70 .
  • the safety switching device 70 differs from the safety switching device 40 shown in FIG. 2 primarily by having a logic AND link, which is annotated by reference number 72 in FIG. 6 .
  • the output of the AND gate 72 is supplied to the signaling unit 54 .
  • the AND gate 72 receives at a first input the disconnection signal from a tripping element 74 , which in this case has two channels and, by way of example, is a two-channel EMERGENCY-OFF button here.
  • the AND gate 72 receives a signal which is derived from the operating voltage U B .
  • the defined signal state whose presence causes the safety switching device 70 to initiate switching off the machine 42 , thus corresponds both to absence of the operating voltage U B and to operation of the tripping element 74 , or even to both.

Landscapes

  • Safety Devices In Control Systems (AREA)
  • Electronic Switches (AREA)
  • Keying Circuit Devices (AREA)
  • Relay Circuits (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Control Of Electric Motors In General (AREA)
  • Pinball Game Machines (AREA)
US10/355,703 2000-08-01 2003-01-31 Safety switching device for safely switching off an electrical load Expired - Fee Related US6809911B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE10037383 2000-08-01
DE10037383.6 2000-08-01
DE10037383A DE10037383A1 (de) 2000-08-01 2000-08-01 Sicherheitsschaltgerät zum sicheren Abschalten eines elektrischen Verbrauchers, insbesondere einer elektrisch angetriebenen Maschine
PCT/EP2001/008805 WO2002011165A1 (de) 2000-08-01 2001-07-30 Sicherheitsschaltgerät zum sicheren abschalten eines elektrischen verbrauchers, insbesondere einer elektrisch angetriebenen maschine

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2001/008805 Continuation WO2002011165A1 (de) 2000-08-01 2001-07-30 Sicherheitsschaltgerät zum sicheren abschalten eines elektrischen verbrauchers, insbesondere einer elektrisch angetriebenen maschine

Publications (2)

Publication Number Publication Date
US20030137788A1 US20030137788A1 (en) 2003-07-24
US6809911B2 true US6809911B2 (en) 2004-10-26

Family

ID=7650902

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/355,703 Expired - Fee Related US6809911B2 (en) 2000-08-01 2003-01-31 Safety switching device for safely switching off an electrical load

Country Status (7)

Country Link
US (1) US6809911B2 (de)
EP (1) EP1307894B1 (de)
JP (1) JP4824897B2 (de)
AT (1) ATE366991T1 (de)
AU (1) AU2001283969A1 (de)
DE (2) DE10037383A1 (de)
WO (1) WO2002011165A1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060072265A1 (en) * 2004-10-06 2006-04-06 Teknic, Inc. Power and safety control hub
US20060274459A1 (en) * 2003-03-21 2006-12-07 Xin Zhou Modular contactor assembly having independently controllable contactors
US20080176389A1 (en) * 2004-03-26 2008-07-24 Masayuki Tanaka Semiconductor memory device and method of manufacturing the same
US9852852B2 (en) 2012-04-05 2017-12-26 Pilz Gmbh & Co. Kg Safety switching apparatus with switching element in the auxiliary contact current path
US20180350541A1 (en) * 2017-06-02 2018-12-06 Sick Ag Modular safety relay circuit for the safe switching on and/or off of at least one machine
US10360790B2 (en) 2016-04-22 2019-07-23 Banner Engineering Corp. Safety touch button system having an intercommunications link

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10045651B4 (de) * 2000-09-15 2007-08-02 Pilz Gmbh & Co. Kg Sicherheitsschaltgerät
DE10220349B4 (de) * 2002-01-31 2005-09-22 Siemens Ag Verfahren und Vorrichtung zum Verbinden einer Versorgungsgleichspannung mit einer Last und zum Trennen der Versorgungsgleichspannung von der Last
DE102011075212B3 (de) * 2011-05-04 2012-07-12 Lindauer Dornier Gmbh Webmaschine und Verfahren zum sicheren Halt einer Webmaschine mit mehreren Antriebsmotoren

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4053876A (en) * 1976-04-08 1977-10-11 Sidney Hoffman Alarm system for warning of unbalance or failure of one or more phases of a multi-phase high-current load
US4068773A (en) * 1975-04-03 1978-01-17 Allis-Chalmers Corporation Lift vehicle with fail-safe overload protective system
US4085823A (en) * 1975-11-03 1978-04-25 Westinghouse Electric Corporation Elevator system
DE3642233A1 (de) 1986-12-10 1988-06-23 Steuerungselektronik Schoefman Einrichtung fuer die selbstueberwachung von relaiskontakten
US4769555A (en) * 1985-10-01 1988-09-06 Pulizzi Engineering Inc. Multi-time delay power controller apparatus with time delay turn-on and turn-off
DE4033800A1 (de) 1990-10-24 1992-04-30 Pilz Gmbh & Co Meldeschaltung an einem not-aus-geraet
EP0608477A2 (de) 1993-01-26 1994-08-03 Carlo Gavazzi AG Halbleiterrelais
DE4441171C1 (de) 1994-11-18 1996-02-08 Siemens Ag Schützsicherheitskombination
US5956218A (en) * 1994-08-24 1999-09-21 Aeg Niederspannungstechnik Gmbh & Co. Kg Earth-leakage circuit breaker with automatic monitoring capability
WO1999063561A2 (de) 1998-05-29 1999-12-09 Siemens Aktiengesellschaft Vorrichtung zur sicheren abschaltung einer elektrischen last, mit insbesondere hoher induktivität, von einer elektrischen gleichspannungsversorgung

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19500396C1 (de) * 1995-01-09 1996-02-01 Siemens Ag Sicherheitskombination
SE509479C2 (sv) * 1996-12-09 1999-02-01 Torgny Olsson Säkerhetsrelä och sätt vid återställning av ett säkerhetsrelä

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4068773A (en) * 1975-04-03 1978-01-17 Allis-Chalmers Corporation Lift vehicle with fail-safe overload protective system
US4085823A (en) * 1975-11-03 1978-04-25 Westinghouse Electric Corporation Elevator system
US4053876A (en) * 1976-04-08 1977-10-11 Sidney Hoffman Alarm system for warning of unbalance or failure of one or more phases of a multi-phase high-current load
US4769555A (en) * 1985-10-01 1988-09-06 Pulizzi Engineering Inc. Multi-time delay power controller apparatus with time delay turn-on and turn-off
DE3642233A1 (de) 1986-12-10 1988-06-23 Steuerungselektronik Schoefman Einrichtung fuer die selbstueberwachung von relaiskontakten
DE4033800A1 (de) 1990-10-24 1992-04-30 Pilz Gmbh & Co Meldeschaltung an einem not-aus-geraet
EP0608477A2 (de) 1993-01-26 1994-08-03 Carlo Gavazzi AG Halbleiterrelais
US5406442A (en) 1993-01-26 1995-04-11 Carlo Gavazzi Ag Solid state relay
US5956218A (en) * 1994-08-24 1999-09-21 Aeg Niederspannungstechnik Gmbh & Co. Kg Earth-leakage circuit breaker with automatic monitoring capability
DE4441171C1 (de) 1994-11-18 1996-02-08 Siemens Ag Schützsicherheitskombination
WO1999063561A2 (de) 1998-05-29 1999-12-09 Siemens Aktiengesellschaft Vorrichtung zur sicheren abschaltung einer elektrischen last, mit insbesondere hoher induktivität, von einer elektrischen gleichspannungsversorgung
US20010002101A1 (en) 1998-05-29 2001-05-31 Bjorn Magnussen Apparatus for safely disconnecting an electrical load from an electrical DC voltage supply

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060274459A1 (en) * 2003-03-21 2006-12-07 Xin Zhou Modular contactor assembly having independently controllable contactors
US7196434B2 (en) * 2003-03-21 2007-03-27 Eaton Corporation Modular contactor assembly having independently controllable contractors
US20080176389A1 (en) * 2004-03-26 2008-07-24 Masayuki Tanaka Semiconductor memory device and method of manufacturing the same
US20060072265A1 (en) * 2004-10-06 2006-04-06 Teknic, Inc. Power and safety control hub
US7453677B2 (en) 2004-10-06 2008-11-18 Teknic, Inc. Power and safety control hub
US9852852B2 (en) 2012-04-05 2017-12-26 Pilz Gmbh & Co. Kg Safety switching apparatus with switching element in the auxiliary contact current path
US10360790B2 (en) 2016-04-22 2019-07-23 Banner Engineering Corp. Safety touch button system having an intercommunications link
US20180350541A1 (en) * 2017-06-02 2018-12-06 Sick Ag Modular safety relay circuit for the safe switching on and/or off of at least one machine
US11101091B2 (en) * 2017-06-02 2021-08-24 Sick Ag Modular safety relay circuit for the safe switching on and/or off of at least one machine

Also Published As

Publication number Publication date
EP1307894B1 (de) 2007-07-11
JP2004505600A (ja) 2004-02-19
US20030137788A1 (en) 2003-07-24
DE50112721D1 (de) 2007-08-23
DE10037383A1 (de) 2002-02-21
ATE366991T1 (de) 2007-08-15
AU2001283969A1 (en) 2002-02-13
JP4824897B2 (ja) 2011-11-30
WO2002011165A1 (de) 2002-02-07
EP1307894A1 (de) 2003-05-07

Similar Documents

Publication Publication Date Title
US6570272B2 (en) Safety switching device for connection and safe disconnection of an electrical load, in particular an electrically driven machine
US6628015B2 (en) Safety switching device and system of safety switching devices
US6809911B2 (en) Safety switching device for safely switching off an electrical load
US6611416B1 (en) Safety relay circuit for large power contactors
US7304406B2 (en) Control device for safety-critical components and corresponding method
JP3831611B2 (ja) 高いインダクタンスを有する電気的負荷を直流電圧源から遮断するための装置
CN101494135B (zh) 继电器电路
US6236553B1 (en) Safety relay
CN109216113A (zh) 继电器装置
US10186391B2 (en) Circuit breaking system
JP4176186B2 (ja) 機械等を起動するための回路及び起動を制御する方法
JP7513807B1 (ja) 接点出力装置
US20120139362A1 (en) Fail-Safe Switching Module
US7579719B2 (en) Protector suitable for cascade connections and corresponding method for safety-conditioned switching
JPH1132427A (ja) 配電システム
KR100986004B1 (ko) Ｐｌｃ 시스템의 지능형 입출력 모듈
JP2797221B2 (ja) 電源の起動停止回路
SU1001298A1 (ru) Самоконтролирующа с система электропитани посто нного напр жени
SU1259384A1 (ru) Устройство дл автоматического повторного включени высоковольтного выключател
JP2022135325A (ja) 故障検知リレー回路
CN117916837A (zh) 电开关装置
SU1372417A1 (ru) Устройство дл индикации состо ни плавкого предохранител
RU1812590C (ru) Устройство дл защиты от ложного срабатывани исполнительных элементов электроустановки
SU1598048A1 (ru) Агрегат бесперебойного питани
JPH11216620A (ja) 放電加工用電源装置における障害検知方法、放電加工用電源装置の制御方法及び放電加工用電源装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: PILZ GMBH & CO., GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:DICKHOFF, ROLF;GRAF, WINFRIED;REEL/FRAME:013899/0347

Effective date: 20030203

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

CC Certificate of correction
FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20121026